The two officials confirmed to The Associated Press that the airstrikes began this month but wouldn't elaborate on their outcome.

U.S. military spokesman in Kabul, Brig. Gen. Charles Cleveland, said U.S. forces "have conducted a limited number of strikes under these new authorities" but that it is "too early to quantify the effects achieved."

The strikes "are only being used where they may help the Afghans achieve a strategic effect," Cleveland said, stressing that the U.S. military is "still in the process of fully operationalizing new authorities."

In Washington, Pentagon spokesman, Navy Capt. Jeff Davis, told the AP that the expanded U.S. military authorities have been in effect for about the last week or so.

Obama decided in early June to expand America's involvement with more airstrikes against insurgents, giving the U.S. military wider latitude to support Afghan forces, both in the air and on the ground.

Since all foreign combat troops pulled out of Afghanistan at the end of 2014, leaving only an advisory and training contingent of international forces behind, the Afghan military has struggled in leading the fight against the Taliban and other militants.

The 9,800 remaining U.S. troops in Afghanistan are scheduled to drop to 5,500 by the end of this year, but the pace of that decline has yet to be decided. One factor in determining future troop levels is the extent to which NATO allies are willing to remain involved in training and advising the Afghans.